Biowarfare, Bioterrorism, and Animal Diseases as Bioweapons

Between 1936 and 1980, more than 100 definitions for
terrorism were coined. 110 Within the USA, two official definitions
of terrorism have been used since the early 1980s; the
Department of State uses one for accounting purposes (statistical
and analytical endpoints), and the U.S. Congress uses
the other for criminal proceedings (“act of terrorism”). 57 The
context of bioterrorism within this chapter follows a recent
definition in the scientific literature and is separated from
biowarfare on the basis of the latter involving a declaration of
war or the perception of war being waged between nations as
evidenced by an appropriate level of hostile actions between
nations. Keeping that distinction in mind, “Bioterrorism
is the intentional use of microorganisms or toxins derived
from living organisms to cause death or disease in humans,
animals, or plants on which we depend.” 77
Past Biowarfare and Bioterrorism
“A man may imagine things that are false, but he can only
understand things that are true.” (Isaac Newton) 2
The ravages of naturally occurring disease documented
throughout history 2,6–11 substantiate infectious disease use as
potential weapons among enemies. In fact, biological warfare
was used in varying degrees well before the germ theory for
disease was first proposed in 1530, 12 demonstrating that infectious
disease used as weapons against humans and animals
is not a new concept. 13–16
Plague and Smallpox as Bioweapons
The 1346 Siege of Caffa (also spelled Kaffa, which is
now Feodosija, Ukraine) involved the most gruesome and
crudest example of biological warfare when the Mongol
army catapulted plague-infected cadavers into the besieged
city. “Mountains of dead were thrown into the city,” infecting
the inhabitants and resulting in many deaths from the
Black Death (plague). However, plague also devastated the
Mongols attacking the city and the infected cadavers did not
alter the outcome of the siege. Furthermore, fleeing survivors
were not a major factor in plague spreading from Caffa to the
Mediterranean Basin because of other factors contributing to
the plague epidemic. 16,17
Plague is a zoonotic disease caused by the bacterium Yersinia
pestis, typically harbored by wild rodents (Fig. 6.2). The
plague epidemic that swept through Europe, the Near East,
and North Africa in the mid-14 th century was probably the
greatest public health disaster in recorded history. An estimated
one-quarter to one-third of Europe’s population died
from plague during the 14 th century pandemic, and North
Africa, the Near East, and perhaps the Far East had similar
high levels of mortality. 16,18 However, the first recorded plague
pandemic began in 541 in Egypt when the world population
was considerably smaller and decimated an even greater
percentage of the population. This pandemic swept across
234 Disease Emergence and Resurgence: The Wildlife–Human Connection
Europe and parts of Asia; between 50 and 60 percent of the
human population died in many areas. 19,20
Given the explosive nature and history of disease spread
over wide areas, plague could be a dangerously effective
biological weapon 18,20, 21 and nations pursuing bioweapons
development have often focused on this agent. During World
War II (WWII), Japan successfully initiated plague epidemics
in China by releasing as many as 15 million laboratoryinfected
fleas per attack from aircraft over Chinese cities. 22,23
Nevertheless, the complexity of biological factors involved
in plague transmission results in fleas being unreliable as a
delivery system for biowarfare.
Early in the history of the Black Death, the original
bubonic-flea-borne variety of plague evolved to the far more
contagious pneumonic variety as a cause of human epidemics.
1 Direct human exposure by aerosolized plague bacilli is
the most effective way to cause human illness and death; 19,24,25
the biological weapons programs of the USA and the former
Soviet Union have pursued aerosol transmission capabilities
for plague. 19,26,27 The Soviets had intercontinental ballistic
missile warheads containing plague bacilli available for
launch before 1985. 28 Yet, virtually insurmountable problems
arose in the production and aerosol dispersal of substantial
quantities of plague organisms by modern weapon systems. 29
Despite these difficulties, plague is viewed as a high-risk
disease for bioweapons. 32
Smallpox also has intentionally been used against humans.
Unlike plague, smallpox is strictly a disease of humans;
it is not zoonotic (Fig. 6.3). 30 In 1763, during the Pontiac
Rebellion (Indian Wars) in North America, contaminated
blankets and a handkerchief from a smallpox hospital were
given as gifts by British forces to Native Americans. This
Trojan horse approach introduced the smallpox virus into
the tribes and caused major casualties. 17,22,31 Capabilities for
aerosol exposure of humans to smallpox exist, while access
to the virus remains tightly controlled following global
eradication of this disease during the 1970s. World Health
Assembly resolution WHA 52.10 called for the destruction
of all remaining stocks of the smallpox virus by the end of
2002, but further evaluation by the World Health Organization
concluded that live virus was needed for specific scientific
purposes. That position was supported by the World Health
Assembly. 208 Virus stocks are maintained for that purpose in
the USA and Russia under international oversight.
Other Applications of Bioweapons Targeting Humans
Numerous reports of using disease as a bioweapon during
times of war exist, but few can be confirmed from available
records. For various reasons, information about the use of
these weapons and their consequences often are unavailable.
From 1932 through WWII, Japan clearly had the most
aggressive biological warfare program ever applied at the
field level. 14,23 This program resulted in the estimated deaths
of at least 10,000 people in laboratory experiments (prisoners